The present invention generally relates to reclosable plastic bags and, more particularly, relates to a reclosable plastic bag having a tamper-evident feature. In one set of embodiments, the plastic bag has a zipper opened and closed using a slider mounted to the zipper, and the tamper-evident feature initially maintains the slider at a closed position on the zipper and allows the slider to move away from the closed position to an open position on the zipper in response to removing or breaking the tamper-evident feature. In another set of embodiments, the tamper-evident feature initially maintains a mouth portion of the plastic bag in a folded position and allows the mouth portion to be unfolded in response to removing or breaking the tamper-evident feature.
Reclosable slider bags of the type disclosed in U.S. Pat. No. 5,067,208 include a zipper that is opened and closed by movement of a slider mounted to the zipper. Due to the ease of operating the slider, such slider bags have increased in popularity over the last few years. Heretofore, the primary market for slider bags has been consumers who purchase a package of empty slider bags and then fill the slider bags with products at home. However, with the increasing popularity of the slider bags, product manufacturers have become interested in packaging their food and nonfood products in slider bags for sale to consumers. The slider bags are a great convenience to the consumer who purchases these product-filled bags especially for products of the type where only a portion of the product is used at any given time. The product applications for which slider bags may be useful are virtually unlimited. The consumer may initially open the slider bag, use a portion of the product, and then easily reclose the slider bag. Due to the ease of using the slider bag, the slider bag is typically preferred over one-time openable bags, which are significantly more difficult to open and reclose. To open a one-time openable bag, the consumer may need to tear the bag open and may require a scissors or other tool to facilitate the opening process; to reclose the bag, the consumer typically must roll the top of the bag closed and may require an extra fastening mechanism such as a clip, tie, or tape to maintain the bag in the closed position.
A problem with plastic slider bags is that if such bags are to be prepackaged with a food or non-food product and then sold in a store, the contents of the plastic bags can easily be tampered with prior to purchase by the consumer. To inhibit such tampering, slider bags have been provided with tamper-evident features of the type disclosed in U.S. Pat. Nos. 5,669,715; 5,713,669; and 5,775,812. While such tamper-evident features are capable of providing tamper evidence upon opening the bag, bag manufacturers such as the assignee of the foregoing patents are continually striving to develop new bag features for improving the functionality of their bags.
To that end, the present invention provides a plastic bag comprising first and second opposing body panels fixedly connected to each other along a pair of sides and a bottom bridging the pair of sides. The bag is provided with a reclosable zipper extending along a mouth portion formed opposite the sealed bottom of the plastic bag. The zipper is preferably free of graspable upper pull flanges in order to best accommodate a slider and inhibit operation of the zipper without the slider. The slider is slidably mounted to the zipper for movement between a closed position and an open position. The zipper is closed while the slider is in the closed position. The zipper is opened in response to movement of the slider to the open position. The bag optionally includes end terminations at opposite ends of the zipper to prevent the slider from going past the ends of the zipper. To provide the plastic bag with tamper evidence, the bag includes a tamper-evident feature.
In one set of embodiments, the tamper-evident feature initially maintains the slider in the closed position and allows the slider to move away from the closed position toward the open position in response to removing or breaking the tamper-evident feature. The tamper-evident feature may take a variety of forms including for example: a removable cardboard, paper, or plastic member covering or adjacent to the slider in the closed position and adhered, stapled, friction fit, or connected in some other way to the bag to hold the member in place; a removable flexible member extending through a hole in the slider or through a hole in the zipper adjacent to the slider in the closed position; a removable stepped retaining element removably attached to one of the bag body panels near the closed position of the slider such that a shoulder of the slider is initially engaged to the stepped element and is disengaged therefrom upon removal of the stepped element; a latch connected to the end termination and releasably engaged to the slider in the closed position; a latch connected to the slider and releasably engaged to the end termination when the slider is in the closed position; and a removable U-shaped element extending through slots in the slider in the closed position and dug into the zipper.
The tamper-evident features noted above initially maintain the slider in the closed position. Therefore, prior to removing or breaking the tamper-evident feature, it is difficult to gain access to the interior of the bag because, in the absence of graspable upper flanges, the zipper is difficult to grasp and open by hand without the use of the slider. After the tamper-evident feature is removed or broken, the slider may be used to open the zipper and access the contents of the bag.
In another set of embodiments, the tamper-evident feature initially maintains the mouth portion of the plastic bag in a folded position and allows the mouth portion to be unfolded in response to removing or breaking the tamper-evident feature. The tamper-evident feature can be employed with both slider and sliderless bags and may take a variety of forms including for example: spot seals detachably sealing the sides of the folded mouth portion to the sides of the bag; spot seals detachably sealing the inner panel of the folded mouth portion to the adjacent bag panel; a removable flexible member passing through both the folded mouth portion and the adjacent unfolded portion of the bag; one or more stickers (adhesive strips) attaching the folded mouth portion to the adjacent unfolded portion of the bag; and combinations of the foregoing. If the flexible member or sticker is employed and the plastic bag includes a slider for operating the zipper, the flexible member or sticker may be strategically positioned to perform the dual function of maintaining the mouth portion in the folded position and preventing the slider from being moved away from the closed position until the flexible member or sticker is removed from the bag.
The tamper evident features of the present invention effectively inhibit tampering with contents of the bag to a degree that is especially useful for non-food and some food applications, where tamper-proof packaging is not required but tamper-resistant packaging is nonetheless desirable.